U.S. patent number 11,267,263 [Application Number 16/605,719] was granted by the patent office on 2022-03-08 for moveable platen ribs.
This patent grant is currently assigned to Hewlett-Packard Development Company, L.P.. The grantee listed for this patent is Hewlett-Packard Development Company, L.P.. Invention is credited to Wesley Chia, Wei Lit Teoh, Wee Hien Tok, Xu-Gang Wang.
United States Patent |
11,267,263 |
Tok , et al. |
March 8, 2022 |
Moveable platen ribs
Abstract
An apparatus (102) with moveable platen ribs (110,112), is
described. The apparatus comprises a platen (108) for supporting
print media (106). The platen extends in a plane in which the print
media is conveyed to be printed. The apparatus further includes a
first set of platen ribs (110) and a second set of platen ribs
(112) each mounted on the platen. The second set of platen ribs are
moveable approximately perpendicular to the plane.
Inventors: |
Tok; Wee Hien (Singapore,
SG), Chia; Wesley (Singapore, SG), Wang;
Xu-Gang (Shanghai, CN), Teoh; Wei Lit (Singapore,
SG) |
Applicant: |
Name |
City |
State |
Country |
Type |
Hewlett-Packard Development Company, L.P. |
Spring |
TX |
US |
|
|
Assignee: |
Hewlett-Packard Development
Company, L.P. (Spring, TX)
|
Family
ID: |
1000006159181 |
Appl.
No.: |
16/605,719 |
Filed: |
April 17, 2017 |
PCT
Filed: |
April 17, 2017 |
PCT No.: |
PCT/CN2017/080815 |
371(c)(1),(2),(4) Date: |
October 16, 2019 |
PCT
Pub. No.: |
WO2018/191850 |
PCT
Pub. Date: |
October 25, 2018 |
Prior Publication Data
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|
Document
Identifier |
Publication Date |
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US 20200130384 A1 |
Apr 30, 2020 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B41J
11/06 (20130101) |
Current International
Class: |
B41J
11/06 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1923524 |
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Mar 2007 |
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CN |
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101229727 |
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Jul 2008 |
|
CN |
|
202412940 |
|
Sep 2012 |
|
CN |
|
202895929 |
|
Apr 2013 |
|
CN |
|
2011183745 |
|
Sep 2011 |
|
JP |
|
201404608 |
|
Feb 2014 |
|
TW |
|
Other References
Printing and Cutting Components, 2007, 4 pages
https://www.google.com/. cited by applicant.
|
Primary Examiner: Valencia; Alejandro
Attorney, Agent or Firm: HP Inc. Patent Department
Claims
We claim:
1. An apparatus comprising: a platen to support a print media,
wherein the platen extends in a plane in which the print media is
conveyed for printing; and a first set of platen ribs and a second
set of platen ribs each mounted to extend approximately
perpendicular from a surface of the platen to contact and support
the print media, wherein each platen rib of the first set of platen
ribs extends a first extent from the surface of the platen, and
each platen rib of the second set of platen ribs is independently
moveable with respect to other platen ribs of the second set of
platen ribs approximately perpendicular to the surface of the
platen and the plane to extend different extents from the surface
of the platen less than and up to the first extent of the first set
of platen ribs.
2. The apparatus as claimed in claimed in claim 1, comprising a
print head and a control engine in communication with the second
set of platen ribs extended approximately perpendicular from the
surface of the platen, wherein the control engine is to: obtain
values of print-related parameters corresponding to a printing
operation; based on the values of the print-related parameters,
estimating occurrence of physical changes in the print media during
the printing operation; and based on estimating, generating control
signals for actuating any one of the second set of platen ribs to
move approximately perpendicular to the surface of the platen and
the plane and control spacing between the print media and the print
head.
3. The apparatus as claimed in claim 1, wherein the second set of
platen ribs are to contact and support portions of the print media
in proximity to edges of the print media.
4. The apparatus as claimed in claim 2, wherein the print-related
parameters comprise attributes pertaining to one of a print job
corresponding to the printing operation and physical properties of
the print media.
5. The apparatus as claimed in claim 4, wherein the attributes
pertaining to the print job comprises ink density with which
content is to be printed on the print media.
6. The apparatus as claimed in claim 2, comprising an actuation
mechanism coupled to the control engine, wherein the actuation
mechanism is to: receive the control instructions generated by the
control engine; and based on the control instructions, actuate one
of the second set of platen ribs extended approximately
perpendicular from the surface of the platen to move approximately
perpendicular to the surface of the platen and the plane.
7. The apparatus as claimed in claim 6, wherein the actuation
mechanism comprises a cam-linkage mechanism.
8. The apparatus as claimed in claim 1, wherein the first set of
platen ribs and second set of platen ribs are arranged serially,
with the first set of platen ribs arranged in middle of the second
set of platen ribs.
9. The apparatus as claimed in claim 2, wherein for estimating the
occurrence of the physical changes the control engine is to
further: compare the values with mapping data, wherein the mapping
data correlates the values with indications suggesting that the
print media is likely to undergo the physical change; and
estimating occurrence of the physical change if the value matches
the mapping data.
10. The apparatus as claimed in claim 1, wherein the each of the
second set of platen ribs extended approximately perpendicular from
the surface of the platen is of a different dimension.
11. A method comprising: obtaining values of print-related
parameters corresponding to a printing operation; processing the
values to determine likelihood of occurrence of a physical change
to a print media during the printing operation, the print media
supported by a platen extended in a plane in which the print media
is conveyed during the printing operation; and based on the
likelihood of occurrence of the physical change, controlling
movement of a moveable platen rib from amongst a set of moveable
platen ribs, the set of moveable platen ribs and another set of
platen ribs each extending approximately perpendicular from a
surface of the platen to contact and support the print media, and
each moveable platen rib of the set of moveable platen ribs being
independently moveable with respect to other moveable platen ribs
of the set of moveable platen ribs approximately perpendicular to
the surface of the platen and the plane to extend different extents
from the surface of the platen less than and up to an extent to
which each platen rib of the another set of platen ribs extends
from the surface of the platen.
12. The method as claimed in claim 11, wherein the print-related
parameters comprise attributes pertaining to one of print job
corresponding to the printing operation and physical properties of
the print media.
13. The method as claimed in claim 12, wherein the attributes
comprise physical properties of the print media.
14. The method as claimed in claim 11, wherein the controlling
comprises one of: lowering the set of moveable platen ribs on
determining that the print media is likely to undergo the physical
change; and raising the set of moveable platen ribs on determining
that the print media is not likely to undergo the physical
change.
15. A non-transitory computer-readable medium comprising
instructions executable by a processing resource to: obtain values
of print-related parameters corresponding to a printing operation;
process the values to determine likelihood of occurrence of a
physical change to a print media during the printing operation; and
generate control signals based on the likelihood of occurrence of
the physical change, to affect control of moveable platen ribs to
move between a raised position and a lowered position, wherein the
print media is supported by a platen extended in a plane in which
the print media is conveyed during the printing operation, and
wherein the set of moveable platen ribs and another set of platen
ribs each extend approximately perpendicular from a surface of the
platen to contact and support the print media, and each moveable
platen rib of the set of moveable platen ribs is independently
moveable with respect to other moveable platen ribs of the set of
moveable platen ribs approximately perpendicular to the surface of
the platen and the plane to extend different extents from the
surface of the platen less than and up to an extent to which each
platen rib of the another set of platen ribs extends from the
surface of the platen.
Description
BACKGROUND
Generally, printing operations in inkjet based print devices and
apparatus involve moving a print media with respect to the print
head. The print head ejects a predetermined volume of ink from its
nozzle onto the print media to form characters, which form the
printed content on the print media. During a printing operation,
the print media is supported by a platen. Protrusions on the
platen, referred to as platen ribs, maintain a separation distance
between the print head and the print media. The separation distance
is maintained to avoid placement errors of the ink droplets or to
avoid smearing of the print media with the nozzles of the print
head.
BRIEF DESCRIPTION OF THE DRAWINGS
The following detailed description references the drawings,
wherein:
FIG. 1 is a diagram of an example apparatus including a platen
having a set of moveable platen ribs;
FIG. 2 is a diagram of another example apparatus having a set of
moveable platen ribs for controlling spacing between print media
and print head;
FIG. 3 depicts a front view of an example platen with raised set of
platen ribs;
FIG. 4 depicts a front view of an example platen with lowered set
of platen ribs;
FIG. 5 depicts a top view of another example platen with set of
movable platen ribs;
FIGS. 6-7 depicts a perspective view of an example platen;
FIG. 8 depicts an example method for controlling spacing between
print media and print head of a print apparatus; and
FIG. 9 is a block diagram of an example environment implementing a
non-transitory computer-readable medium, for controlling spacing
between print media and print head.
DETAILED DESCRIPTION
Generally, printing operations in inkjet based apparatus involve
moving a print media with respect to the print head. The print head
ejects a predetermined volume of ink from its nozzles onto the
print media to form characters, forming printed content on the
print media. A separation distance between the print head and the
print media is maintained for desirable print quality. For example,
the separation distance may be close enough to prevent drop
placement errors of the ink droplets. At the same time, a minimum
separation distance may be maintained to avoid the print media
smearing against the nozzle of the print head. If the distance is
less than such a minimum distance, the print media may contact with
the nozzles of print head resulting in obstructions in the print
path causing jams.
It is also observed that the print media may undergo certain
physical changes once ink is deposited. For example, the print
media may curl or get bent at its edges upon ink deposition, or may
experience cockling. On curling or cockling, the separation
distance between the print media and the print head decreases which
may result in smearing or the print media getting jammed. Cockling
may be understood as planar alteration appearing as creases on the
surface of the print media. Such variations, in the otherwise
regular surface of the print media, may decrease the separation
distance between the print head and the print media during
printing.
The print media is supported by a series of platen ribs during the
printing operation. Generally, each of such platen ribs may be
formed as plates and are rigidly mounted on a platen. The platen
ribs are positioned such that the plane in which the platen ribs
lie is approximately perpendicular to the surface of the print
media. The surface of the print media maintains contact with the
edges of the platen ribs as the print media is conveyed during
printing. The platen ribs may be arranged in a series, with
adjacent platen ribs spaced by specific distances. Generally, the
height of the platen ribs varies. For example, certain platen ribs
which are to contact the portions of the print media which lie
about the edges, may be shorter as compared to other platen ribs as
they extend from the surface of the platen. The shorter platen ribs
are to counter any curling which may occur at the edges of the
print media. In such cases owing to the shorter ribs, the distance
between the print head and the print media is maintained even
though the print media may have curled towards the print head.
It is possible that the print media may not always curl during the
printing process. In such cases, the sunken ribs may result in an
increase in the separation distance between the print head and the
print media. Such an increase in the separation distance may
decrease print quality at the edges of the print media. Examples
include variations in contrast, increase in graininess, and
fuzziness in the printed content near the edges of the print
media.
An apparatus with a set of moveable platen ribs is described. The
present description also describes approaches for controlling
separation distance between a print media and a print head of such
an apparatus, through the set of moveable platen ribs. In one
example, the apparatus may include a platen mounted with a first
set and a second set of platen ribs. The first set of platen ribs
may be positioned such that they support a central portion of the
print media. The first set of platen ribs are rigidly mounted on
the platen. The second set of platen ribs are so positioned such
that they correspond to portions lying in proximity to the edges or
corners of the print media. The platen ribs may be formed as plates
which extend approximately perpendicular from the surface of the
platen.
The second set of platen ribs are moveable in a plane in which they
are located. Each of the second set of platen ribs may move between
one or more positions, between a completely raised and a completely
lowered position. In one example, the edges of the second set of
platen ribs when fully extended in the raised position, align with
the edges of the rigidly fixed first set of platen ribs. In a
lowered position, the height of the second set of platen ribs is
less relative to the height of the first set of the platen ribs
with respect to the platen. The second set of platen ribs control
the separation distance between the print media and the print head
of the apparatus. In one example, each of the second set of platen
ribs may be either independently moveable or may move collectively,
without deviating from the scope of the present subject matter. In
another example, the second set of platen ribs may even be grouped
into segments. Each segment of platen ribs may move independently
or in unison with respect to each other.
In operation, values of print-related parameters for a printing
operation may be obtained. The print-related parameters may include
attributes corresponding to an executed print job or physical
properties of the print media. Examples of attributes pertaining to
the print job may include, but not limited to, an ink density;
physical properties of the print media such as size; weight, and
stiffness. The print-related parameters may be considered as
conditions which when present during the printing operation, are
likely to result in physical effects, such as curling, of the print
media. It should be noted that physical effects refer to changes in
the physical attribute of the print media which would result in
variations between the otherwise regular surface of the print
media. Other examples of print-related parameters may also be
relied on without deviating from the scope of the claimed subject
matter.
Returning to the operation of the apparatus, once the values of
print-related parameters are obtained, the likelihood of occurrence
of any physical effects of the print media are estimated. In one
example, the estimation may be based on values of the print-related
parameters. For corresponding values of print-related parameters,
it may be concluded that physical effects of the print media may
occur. Based on such estimation, one or more control instructions
may be generated. Such control instructions when executed may
further actuate an actuation mechanism for raising or lowering the
second set of platen ribs. In one example, if it is determined that
the print media is likely to curl, the control engine may enable
lowering of the set of platen ribs. On the other hand, if it is
determined that the print media is not likely to curl, the set of
platen ribs may be raised to maintain the specific separation
distance between the print media and the print head. An example of
such an actuation mechanism includes, but is not limited to, a cam
and linkage system.
As would be understood, the present subject matter enables
controlling the spacing between the print media and the print head
by assessing whether the print media is likely to curl.
Accordingly, a set of platen ribs may be raised or lowered thereby
preventing the print related artifacts and improving the overall
print quality of the print output. In another example, the
dimensions of the second set of platen ribs may also be unequal. In
such examples, the relative variation between the each of the
second set of platen ribs may occur owing to the different size of
each of the platen ribs, when lowered. The present approaches are
further implemented using less complex mechanisms as are generally
known.
These and other aspects are described in conjunction with various
examples as illustrated in FIGS. 1-8. The present description is
provided for print devices which may have a print carriage
assembly. However, the scope of the present subject matter may not
be limited to such print devices. Other types of devices may also
be included within the scope of the present subject matter without
any limitation. Furthermore, in some figures, various components
for which no protection is sought have been illustrated using
dotted lines.
FIG. 1 illustrates an apparatus 102 for controlling spacing between
print media and print head. The apparatus 102 may be implemented as
print devices. Print devices may include printers or other
multifunction devices which may which perform other functions, such
as a scanning, in addition to printing. In the present example, the
apparatus 102 may include a print head 104. The print head 104 may
include one or more nozzles through which a predefined volume of
ink is ejected and deposited on the print media 106, to form the
printed content. During the printing operation, the print media 106
is supported on platen 108. The platen 108 may further be provided
with a first set of platen ribs 110-1, 2, . . . , N (referred to as
platen ribs 110) and a second set of platen ribs 112-1, 2, . . . ,
N (referred to as platen ribs 112). The platen ribs 110 may be
formed as plates which extend from the surface of the platen 108 in
an approximately perpendicular direction. During the printing
operation, the print media 106 is supported by the platen ribs 110
and 112 as the print media 106 is conveyed through the print path
in the apparatus 102.
Of the platen ribs 110 and 112, the first set of platen ribs 110
are rigidly mounted on the platen 108. The second set of platen
ribs 112 also extend approximately perpendicular from the surface
and are moveable with respect to the platen 108 (as is indicated in
FIG. 1). In one example, each of the second set of platen ribs 112
may move between a raised and a lowered position. In the raised
position, the height of the second set of platen ribs 112 is
comparable and approximately equal to the height of the first set
of platen ribs 110. Correspondingly, in a lowered position the
height of the second set of platen ribs 112 is less than the height
of the first set of platen ribs 110.
The second set of platen ribs 112 are so positioned such that they
support the corners or edges of the print media 106. During the
printing operation, the second set of platen ribs 112 may be moved
between a raised and lowered position depending on whether the
print media 106 undergoes any physical changes which may decrease
an overall separation distance between the print head 104 and the
print media 106. If it is determined that the print media 106 is
not likely to undergo any physical changes, the second set of
platen ribs 112 may be fully extended in the raised position such
that the furthermost edges of the second set of platen ribs 112 are
aligned with the edges of the first set of platen ribs 110. Thus,
the separation distance between the print head 104 and the print
media 106 is maintained. On other hand, if it is determined that
the print media 106 is likely to undergo any physical change, one
or more of the second set of platen ribs 112 may be lowered. For
example, it may be the case that the print media 106 is likely to
curl up towards the print head 104 thereby decreasing the
separation distance. In such a case, one or more of the second set
of platen ribs 112 may be lowered such that the separation distance
between the print head 104 and the print media 106 is maintained.
The second set of platen ribs 112 may be controlled either
individually or collectively. In one example, the print-related
parameters may be utilized for determining whether any physical
changes to the print media 106 are likely to occur during the
printing operation. Accordingly, the second set of platen ribs 112
may be raised or lowered depending on values of the print-related
parameters.
Apparatus and approaches as described allow raising and lowering
the second set of platen ribs 112 to control spacing between print
media and print head. Furthermore, the second set of platen ribs
112 may be raised or lowered depending on print-related parameters
which in turn indicate whether the print media 106 is likely to
undergo any physical changes. Such physical changes, as explained
previously, result in a change in the separation distance between
the print head 104 and the print media 106. As per one example, the
likelihood of physical changes may be preempted, and accordingly
the ribs lowered thereby ensuring that the separation distance is
within a prescribed range. This in turn reduces fuzziness and
graininess of the image, thereby improving print quality.
These and other examples are provided in further detail in
conjunction with the remaining figures. FIG. 2 illustrates the
apparatus 102 which, in one example, may be implemented as a print
device. The apparatus 102 as illustrated in FIG. 2 may be
implemented using programmable logic, either by way of hardware or
software. In the present example, the apparatus 102 includes an
interface(s) 202, memory(s) 204 and second set of platen ribs 112
(referred to as platen ribs 112). The interface(s) 202 may include
a variety of interfaces, for example, interfaces for data input and
output devices, referred to as I/O devices, storage devices,
network devices, and the like. The interface(s) 202 facilitate
communication between the apparatus 102 and other computing devices
connected in a networked environment. In one example, the
interface(s) 202 may provide an interface for communication between
the apparatus 102 and the display unit 202. The memory 204 may
store one or more computer-readable instructions, which may be
fetched and executed, resulting in generating an alert to enable a
user to retrieve a printed document. The memory 204 may include any
non-transitory computer-readable medium including, for example,
volatile memory such as RAM, or non-volatile memory such as EPROM,
flash memory, and the like. The apparatus 102 further includes
engine(s) 206 and data 208.
The apparatus 102 further includes an actuation mechanism 210. The
actuation mechanism 210 may be in communication with the any one of
the engine(s) 206. The actuation mechanism 210 is also mechanically
coupled to each of the second set of platen ribs 112. The engine(s)
206 during the operation of the apparatus 102 may generate control
signals for operating the actuation mechanism 210. On receiving the
control signals, the actuation mechanism 210 may enable moving of
the platen ribs 112 between a raised and lowered position.
The engine(s) 206 may be implemented as a combination of hardware
and programming (for example, programmable instructions) to
implement one or more functionalities of the engine(s) 206. In
examples described herein, such combinations of hardware and
programming may be implemented in a number of different ways. For
example, the programming for the engine(s) 206 may be processor
executable instructions stored on a non-transitory machine-readable
storage medium and the hardware for the engine(s) 206 may include a
processing resource (for example, one or more processors), to
execute such instructions. In the present examples, the
machine-readable storage medium may store instructions that, when
executed by the processing resource, implement engine(s) 206. In
such examples, the apparatus 102 may include the machine-readable
storage medium storing the instructions and the processing resource
to execute the instructions, or the machine-readable storage medium
may be separate but accessible to apparatus 102 and the processing
resource. In other examples, engine(s) 206 may be implemented by
electronic circuitry.
The data 208 includes data that is either predefined or generated
as a result of the functionalities implemented by any of the
engine(s) 206. In an example, the engine(s) 206 include the control
engine(s) 212, and other engine(s) 214. The other engine(s) 214 may
implement functionalities that supplement applications or functions
performed by the apparatus 102. Further, the data 208 may include
values of print-related parameters (referred to as parameter values
216), mapping data 218 and other data 220.
As mentioned previously, the second set of platen ribs 112 are
moveable with respect to a platen 108. The platen ribs 112 may move
in a direction which is approximately orthogonal to the plane in
which the platen 108 is present. The platen ribs 112 may be either
in a raised position or a lowered position. For example, the platen
ribs 112 may be in a lowered position if the print media 106 is
likely to undergo curling or any other physical changes. Similarly,
if it is determined that the print media 106 is not likely to
undergo any changes, then the platen ribs 112 may be in a raised
position. While the platen ribs 112 is in a lowered position, the
relative height of the platen ribs 112 is less than the height of
the first set of platen ribs 110 (shown in FIG. 1). Conversely,
while in the raised position, the height of the platen ribs 112 is
comparable or equal to the height of the first set of platen ribs
110.
In one example, the control engine(s) 212 may control the movement
of the platen ribs 112. To this end, the control engine(s) 212 may
determine one or more values of print-related parameters (i.e.,
parameter values 216) for a print job. A print job may be
considered as any printing operation that may have to be executed
or performed by the apparatus 102 in response to a print command
from a user. The print job may generally define the content which
is to be printed, say, on the print media 106. The instructions
from the user may be processed by a computing device (not shown in
FIG. 2). Such a computing device may then transmit such
instructions to the apparatus 102. Based on the instructions; the
apparatus 102 determines the manner in which the content is to be
rendered, i.e., printed, onto the print media.
The print-related parameters may be considered as defining one or
more parameters based on which a print device, such as the
apparatus 102, processes instructions and prints content on a print
media 106. For example, if the content involves areas having darker
tones, the corresponding print-related parameters may prescribe
certain values based on which the apparatus 102 determines which
type of ink or volume of ink that needs to be ejected from the
print head 104. The print-related parameters may also prescribe the
type of print media 106 that may have to be used for printing a
desired content. For example, it is possible that content may have
to be printed on a print media 106 which is stiffer or perhaps even
larger in size. The parameter values 216 may provide one or more
values depicting such different conditions which may be present or
have to be considered while processing a print job.
Continuing with the present example, the apparatus 102 may receive
a print command indicative of a print job. The control engine(s)
212 may obtain the values of the print-related parameters from the
print command. The control engine(s) 212 may store the values as
parameter values 216. The control engine(s) 212, based on the
parameter values 216, may estimate whether the print media 106 is
likely to undergo any physical changes (such as curling) during the
printing operation. In one example, the control engine(s) 212 may
compare the parameter values 216 with the mapping data 218. The
mapping data 218 may provide a mapping between one or more
parameter values 216 with indications suggesting that the print
media 106 is likely to undergo a change. For example, parameter
values 216 indicating a high ink density may be considered as
possible conditions for occurrence of curling in the print media
106. Similarly, a parameter values 216 indicating that a stiffer
print media 106 is being utilized may be indicated as a condition
which will not result in any physical changes in the print media
106. It should be noted that the examples relied are only
indicative and not limiting. Other examples of parameter values 216
and corresponding conditions may also be used, without deviating
from the scope of the claimed subject matter. In another example,
the parameter values 216 may be either user prescribed or may be
based on historical or other analytical data.
Once the control engine(s) 212 determines the likelihood that any
physical changes to the print media 106 are likely to occur, it may
further control the platen ribs 112 and move them to a position
between a raised and lowered position. For example, the control
engine(s) 212 may determine, based on the parameter values 216,
that the ink density is high for the print job under consideration.
Accordingly, the control engine(s) 212 may conclude that the print
media 106 is likely to curl during the printing operation. The
manner in which the platen ribs 112 are operated is further
explained in conjunction with FIGS. 3-4. FIGS. 3-4 depicts
different instances in which the platen ribs 112 are fully raised
(depicted as platen ribs 312) and when lowered (depicted as platen
ribs 412).
Returning to the present example, the control engine(s) 212 on
determining that the print media 106 is not likely to undergo any
physical changes (such as curling) may generate one or more control
signals for the actuation mechanism 210. As mentioned before, the
separation distance between the print head 104 and the print media
106 would not vary in case the print media 106 does not undergo any
curling. In such a case, the control engine(s) 212 may control the
platen ribs to be in a raised position (depicted as ribs 312-1, 2,
. . . , N). The raised ribs 312 are such that their relative height
with respect to the platen 108 remains similar to the height of the
first set of platen ribs 110. The control engine(s) 212 may proceed
and generate control instructions for raising the second set of
platen ribs 112. The second set of platen ribs 112 continues to
move in the direction as indicated such that they are fully raised
(as raised ribs 312 depicted in FIG. 3).
It may also be the case that the control engine(s) 212 may
determine that the print media 106 is likely to curl during the
printing operation. For example, the parameter values 216 may
indicate that the ink density for the print job under consideration
is greater than a threshold value. For the high ink density, the
control engine(s) 212 may conclude that the print media 106 is
likely to curl up towards the print head 104. Accordingly, the
control engine(s) 212 may generate control signals for lowering
selected platen ribs 112 from its raised position (as depicted in
FIG. 4). The platen ribs 112 may be lowered in direction as shown
in FIG. 4 such that the relative height of the lowered ribs (i.e.,
ribs 412-1 and 2--collectively referred to as ribs 412) is less
than the height of the first set of platen ribs 110. In one
example, the height to which the ribs 412 is lowered may vary
between each of the lowered ribs 412. For example, as is
illustrated, the height of the rib 412-1 differs from the height of
the rib 412-2 even though the both the ribs 412-1 and 2 were
lowered. The height of further ribs 412 may also be different. In
the present example, the lowering of the ribs 412 is to counter the
curling of the print media 106. The placement of the ribs 412
enable to maintain an optimal separation distance between the print
head 104 and print media 106. As described, the present subject
matter provides a set of moveable platen ribs which may be raised
or lowered depending on whether the print media 106 is likely to
curl or not. Preempting such a condition and accordingly raising
and lowering the second set of platen ribs 112 improves print
quality.
In the example as depicted in FIG. 4, the ribs 412 may be further
grouped in two or more segments. For example, the segments 414-A, B
may be so positioned such that they are present on either side of
the first set of platen ribs 110. In one example, each of the ribs
412 (present in both segments 414-A, B) may be moveable together.
In another example, motion of the segment 414-A may be independent
from the motion of segment 414-B. In such a case, the actuation
mechanism for the segment 414-A may be different from the actuation
mechanism for the segment 414-B, without deviating from the scope
of the present subject matter.
FIG. 5 is a top view of an example platen having rigid and moveable
platen ribs. The platen 500 includes a first set of platen ribs 110
and a second set of platen ribs 112. The first set of platen ribs
110 is rigidly attached to the platen 500. The second set of platen
ribs 112 on the other hand are moveable and may be lowered or
raised orthogonally with respect to the platen 500. Each of the
second set of platen ribs 112 is coupled to a shaft 502 through a
connecting link 504. The connecting link 504 may be further coupled
to a cam arrangement (not shown in FIG. 5) for each of the second
set of platen ribs 112. The cam arrangement enables reciprocal
motion of each of the second set of platen ribs 112.
The other end of the shaft 502 is in turn connected to an actuation
mechanism 210. The actuation mechanism 210 actuates the second set
of platen ribs 112 through the shaft 502. The actuation mechanism
210 may move in a direction as is depicted in FIG. 5. The actuating
mechanism may provide an actuation motion which is transferred
through the shaft 502 to each of the second set of platen ribs 112.
The cam arrangement then enable the lowering or raising of one or
more of the second set of platen ribs 112 accordingly. The present
example only indicates a manner for actuating the second set of
platen ribs 112. Other mechanisms for actuating the second set of
platen ribs 112 are also possible and would also be within the
scope of the claimed subject matter. In the present example, each
of the second set of platen ribs 112 may be moveable together owing
to the reciprocating actions of the actuation mechanism 210 which
is transferred through the shaft 502. In another example, each of
the second set of platen ribs 112 may be so configured such that
each of the individual platen ribs 112 move independently of the
other ribs 112. In such instances, each of the second set fo platen
ribs 112 may be connected to their respective shafts and connecting
links, without deviating from the scope of the present subject
matter.
In another example, the platen 108 may be further provided with one
or more ramp profiles coupled with each of the second set of platen
ribs 112. The ramp profiles (not shown in FIG. 5) may be utilized
for defining the extent to which any one of the second set of
platen ribs may be raised. The ramp profiles may be utilized for
defining one or more presets as per which the corresponding platen
ribs 112 is raised but at different heights. The present example is
only one of the other possible example which may be implemented.
Other examples also lie within the scope of the present subject
matter.
In yet another example, each of the second set of platen ribs 112
may be of different dimensions as an alternative to implementing
ramp profiles for raising each of the second set of platen ribs 112
to different extents. Since to the variation in dimensions of each
of the second set of platen ribs 112, the height of second set of
platen ribs 112 when lowered would be varying between the different
second set of platen ribs 112.
FIGS. 6 and 7 depict perspective view of a platen 600 as per
another example of the present subject matter. The platen 600 (as
depicted in FIGS. 6 and 7) illustrate various instances in which
one or more moveable platen ribs may be in a raised or lowered
position. As depicted in FIGS. 6-7, the platen 600 includes a
plurality of rigidly mounted platen ribs 602 and a plurality of
moveable platen ribs 604. The moveable platen ribs 604 may move in
a direction perpendicular to the plane in which the platen 600 is
present. As shown in FIG. 6., the moveable platen ribs 604-1 and 3
are in a lowered position. As explained previously, the moveable
platen ribs 604 may be lowered in cases where it is determined that
the print media 106 (not shown in FIGS. 6-7) may undergo physical
changes, such as curling or cockling. If it is determined that the
print media 106 is not likely to undergo any physical changes, then
each of the moveable platen ribs 604 may be raised (as illustrated
in FIG. 7). When in a raised position, the relative height of the
moveable platen ribs 604 is comparable to the height of the first
set of platen ribs 110.
FIG. 8 illustrates example method 800, implemented in an apparatus
having moveable platen ribs. The moveable platen ribs are used for
controlling separation distance between print media and print head,
as per an example of the present subject matter. The order in which
the method steps are described is not intended to be construed as a
limitation, and any number of the described method blocks may be
combined in any order to implement the aforementioned method, or an
alternative method. Furthermore, method 800 may be implemented by
processing resource or computing device(s) through any suitable
hardware, non-transitory machine readable instructions, or
combination thereof.
At block 802, values of print-related parameters are obtained. In
one example, the control engine(s) 212 may process a print request
to obtain values of print-related parameters. The values are stored
in parameter values 216. As discussed in previous paragraphs,
print-related parameters may be considered as defining one or more
parameters based on which a print device, such as the apparatus
102, processes instructions and prints content on a print media
106. The parameter values 216 may provide one or more values
depicting such different conditions which may be present, or may
have to be considered while processing a print job.
At block 804, the values of the print-related parameters are
processed to determined likelihood of physical change of a print
media. For example, the control engine(s) 212 may compare the
parameter values 216 with mapping data 218. In the present example,
the mapping data 218 may provide a mapping between one or more
parameter values 216 with indications suggesting that the print
media 106 is likely to undergo a change.
At block 806, based on the values of the print-related parameters
one or more moveable platen ribs may be actuated to move between a
raised and a lowered position. For example, based on the parameter
values 216, the control engine(s) 212 may determine whether a
second set of platen ribs 112 coupled are to be moved. To this end,
the control engine(s) 212 may estimate whether the print media 106
is likely to undergo any physical changes during the printing
operation based on the print-related parameters stored as parameter
values 216. In case if it is determined that the print media 106 is
to undergo a physical change, such as curling, the control
engine(s) 212 may further generate one or more control instructions
for lowering the second set of moveable platen ribs 112. Conversely
if it is determined that the print media 106 will not undergo any
physical change, the control engine(s) 212 may generate control
signals to raise the second set of platen ribs 112.
FIG. 9 illustrates an environment 900 for controlling separation
distance between print media and print head of a print apparatus
having a plurality of moveable platen ribs, according to an example
of the present disclosure. The environment 900 may comprise at
least a portion of a public networking environment or a private
networking environment, or a combination thereof. In one
implementation, the environment 900 includes a processing resource
902 communicatively coupled to a computer readable medium 904
through a communication link 906.
In one example, the processing resource 902 may include one or more
processors of a computing device for generating instructions for
moving second set of platen ribs for controlling spacing between
print media and print head. In another example, multiple processors
may also be used for implementing the processing resource 902. The
computer readable medium 904 may be, for example, an internal
memory device of the computing device or an external memory device.
In one implementation, the communication link 906 may be a direct
communication link, such as any memory read/write interface. In
another implementation, the communication link 906 may be an
indirect communication link, such as a network interface. In such a
case, the processing resource 902 can access the computer readable
medium 904 through a network 908. The network 908 may be a single
network or a combination of multiple networks and may use a variety
of different communication protocols.
The processing resource 902 and the computer readable medium 904
may also be coupled to data sources 910 through the communication
link 906, and/or to communication devices 912 over the network 908.
The coupling with the data sources 910 enables in receiving the
data in an offline environment, and the coupling with the
communication devices 912 enables in receiving the data in an
online environment.
In one implementation, the computer readable medium 904 includes a
set of computer readable instructions, implementing a control
module(s) 914. The instructions implementing control module(s) 914
may, in one example, be executable code for moving the second set
of platen ribs 112. The set of computer readable instructions
within medium 904 may be accessed by the processing resource 902
through the communication link 906 and subsequently executed to
process data communicated with the data sources 910 in order to
control spacing between print media and print head of a print
apparatus. To this end, the control module(s) 914 controls one or
more moveable platen ribs of an apparatus, such as the apparatus
102.
The apparatus 102 includes a first set of platen ribs 110 and a
second set of platen ribs 112, each of which are mounted onto a
platen 108 (depicted in FIG. 1). The second set of platen ribs 112
are moveable with respect to the platen 108. The second set of
platen ribs 112 may move between a completely raised position and a
lowered position. As each of the second set of platen ribs 112
move, their relative height with respect to the first set of platen
ribs 110 varies. In operation, the control module(s) 914 may
determine values of one or more print-related parameters. In one
example, the values of the print-related parameters may be obtained
based on a print request from a user. The values may then be stored
in parameter values 216.
Based on the parameter values 216, the control module(s) 914 may
determine whether the print media 106 is likely to under any
physical changes during a printing operation. For example, the
control module(s) 914 may, based on ink density, determine that the
print media 106 will most likely curl during the printing
operation. The control module(s) 914 may compare the parameter
values 216 with mapping data 218 which correlates one or more
parameter values 216 with likely physical changes that may
occur.
On determining whether the print media 106 will undergo any
physical changes, the control module(s) 914 may generate one or
more control instructions for affecting movement of the second set
of platen ribs 112. In the present example, such control
instructions which when executed may activate an actuation
mechanism, for example actuation mechanism 210, for controlling the
second set of platen ribs 112. If it is determined that the print
media 106 is likely to undergo any physical change, for example
curling, the control instructions when executed will raise the
second set of platen ribs 112. When in a raised position, the
relative height of the second set of platen ribs 112 is lower as
compared to the height of the first set of platen ribs 110. On the
other hand, if it is determined that the print media 106 is not
likely to undergo any physical changes, then the control
instructions would be such, that when executed raise the level of
the second set of platen ribs 112.
Although examples for the present disclosure have been described in
language specific to structural features and/or methods, it should
be understood that the appended claims are not necessarily limited
to the specific features or methods described. Rather, the specific
features and methods are disclosed and explained as examples of the
present disclosure.
* * * * *
References